How to simulate reflection of people in a 4 meter parabolic mirror to show that they won't appear upside down?
The mock-up works with Cycles ray-tracing, straightforwardly.
One approach .. You can create the parabolic surface directly, as ShiftA &gt; Mesh &gt; Math Function &gt; Z Math Surface. Perhaps it's easier to extract the profile from a ZX function, curving in only one direction:

.. and having deleted all except the vertices: X&gt;=0, Y=0, spin it with a Screw modifier.

Give the disc a 100% metal, pure White, 0 Roughness, mirror-surface.
The right-way-up virtual image is visible only from certain camera angles.. (if you play, you can see the hall-of-mirrors slide from wrong-way-up to right-way-up).


Maybe, for perfection, you could calculate the ideal normal of the mirror as a function of object-space XY, and plug that into the shader, to get rid of any artefacts resulting from the linear interpolation between vertices.. but for a demo, that doesn't seem to be necessary.